The present invention relates to a liquid filter, in particular for the lubricating oil of an internal combustion engine, comprising at least one replaceable filter and a carrier module.
When a liquid filter element is changed, there is often the problem of residential fluid leading into the environment when screwing open the cover or when exchanging the replaceable filter. This is especially critical with replaceable filters which are installed upright, i.e., with the opening facing downwardly.
U.S. Pat. No. 6,485,637 (=DE 199 61 580) discloses a liquid filter with an outlet for liquid residues. The liquid filter, in particular an oil filter for the lubricating oil for an internal combustion engine, has a suspended housing with a replaceable filter element arranged in it. At the lowest point in the housing vessel, a drain opening is arranged and is automatically opened when the housing vessel is screwed open, whereupon the oil escapes through the drain opening and must be collected in a separate housing.
U.S. Pat. No. 3,724,665 discloses a replaceable oil filter that is positioned upright, i.e., oriented with the opening facing downwardly. The filter housing and filter element are fixedly joined together so that both must be replaced when the filter is changed. To prevent oil equal to the total volume content of the replaceable filter from running out of the housing onto the threaded mounting flange when the filter that is to be replaced is unscrewed, a hollow cylinder is arranged in the interior of the replaceable filter, extending axially and concentrically with the filter element over almost the entire height of the replaceable filter. The oil present in the interior of the hollow cylinder is returned back to the oil circulation when the filter is changed and thus reduces the absolute quantity of oil which escapes. One disadvantage here is that despite the fact that the quantity of oil is reduced, the oil volume that is still present and runs out must be collected in some fashion for environmental reasons. In addition, the escaping oil causes heavy contamination of the threaded mounting flange and any units that might be situated beneath it.